Underwater cutting torch



Muck 51 946. F. N. WllDSQR 9 UNDERWATER CUTTING TORCH Filed Jan." 30', 1941 2 Sheets-Sheet 1 FIG. 1

Frederick N. Windsor WENT BY HIS ATTORNEY March 12, 1946. F. N. WINDSOR UNDERWATER CUTTING TORCH Filed Jan. 30, 1941 2 Sheets-Sheet 2 III I1 0 Fredcri I: N. Win dso HIS ATTORNEY Patented Mar. 12, 1946 UNDERWATER CUTTING TORCH Frederick N. Windsor, Chicago, 111., assignor to The Bastian-Blessing 00., Chicago, 111., a corporation of Illinois Application January 30, 1941, Serial No. 376,664

7 Claims.

The present invention relates to cutting torches and more particularly to new and useful improvements in underwater cutting torch.

In view of the fact that the number of divers available for underwater operations is limited, the volume of business for underwater cutting torches is quite low as compared with conventional above surface torches which will be referred to as dry land torches. Becaus of this, it has been the conventional practice in providing torches for submarine work to convert a dry land torch for that purpose.

Cutting metal under water is a very arduous task confronted with innumerable difliculties which are multiplied for the diver in inverse proportion to the perfection of the equipment used, and, for a better understanding of these difficulties a brief consideration of some of the circumstances involved in making a cut with converted conventional equipment at a substantial depth would be helpful.

When the diver is lowered to his work position, he takes the torch down with him unlighted and lays it on the bottom, signals the surface attendants, and they mark the water line on the hose at the surface. The torch is then raised and lighted. The diver moves well out of the region and the torch is lowered to the marked water line. This is done to prevent the diver being burned, movement in water being retarded enough that a bad burn could be experienced before escape could be had.

When told the torch is down, th diver, swinging his arms in a wide arc moves back to his original position looking for the hose attached to the torch. When found, the torch is lifted'by the hose, and in many cases, the torch in the meantime, has become extinguished, the question of a converted torch remaining lit through all of this being a serious one. If the torch is extinguished, it is returned to the surface and the process is repeated.

On the other hand, if it remains lit, the converted land torch on its way down,has'caught weeds and debris which the diver has to clear away with cumbersome diving gloves on his hands as visioned through a small observation window in his helmet. If the water is muddy, as it is more often than not, this cleaning of the torch is tedious and time consuming.

It is one of the objects of the present invention to provide a torch which will stay lit even though swung violently head-first into the water. Furthermore, to provide a weed free construction upon which weeds and debris will not catch or foul the handle of the cutting oxygen supply.

After the torch has been cleared of impediments, it is brought into working position upon the metal. A blast of shielding gas, for example, oxygen or air, provides an atmospheric bell around the preheat flame which keeps the water away from the flame and the metal, to provide sufficient space in which the flame and cutting stream may function.

With the violent bubbling of water. thus in duced, the diver can see very little of what he is doing and much of his work has to be done by feeling his way and watching the color thrown ofi by his torch.

As the torch flame is held in contact with the work, the blue color becomes tinted with yellow, indicating that the metal is approaching its melting point. The oxygen is then turned on and the metal beginning to burn in the presence of oxygen gives an orange color. Once this color appears, the torch is moved along the surface of the metal to keep up with the oxidizing metal and a kerf is thereby provided.

With all cuts, the diver endeavors to stand below the work point to have a clearer vision of the work, if the water isn't too muddy, but wherever the diver has to work from above the cut, the bubbling action of the gas obstructs all vision and carries the slag of the cut into every crack and crevice of the torch, jamming the mechanism of the converted dry land torch.

It is a further object of the invention to provide a torch construction which is fully protected against slag fouling the moving parts of the torch. I

After a out has been completed, the metal frequently has to be loosened by blows, and for this purpose the torch is constructed to be used as a hammer without injury thereto or a jamming or loosening of the torch adjustments.

It has been mentioned that the torch is lighted above the water. In some instances, where the diver has an electric lighter, the torch can be electrically lighted below the Water but that requires extra equipment to be carried by the diver which might be dangerous if insulation is worn or broken.

With the torch lighted above the water, preadjustment of the flame for subsurface work is difficult, and although endeavors have been made to automatically compensate for the effect of depth, individual preferences of divers still require sub-surface adjustments.

Another object of the invention is to provide an improved control arrangement which permits the diver to adjust the flame to his own liking and once adjusted by the diver, the invention provides an improved tip holding device and air bell construction which maintains the flame characteristics substantially the same over a substantial range of depths without further adjustment. This latter feature serves also to maintain the flame lighted while being lowered after the torch has been lighted at the surface.

The present invention further provides an ar rangement of passages through body portions in relation to the ultimate location of gas conduits in the cutting head so that the parts may be machined easily, yet have the arrangement such that the diver can control every phase of the operation of the torch by conveniently arranged valves positioned where they are readily accessible and permit the heel of the torch to rest snugly against and be supported by the wrist and fore-arm of the diver.

A further purpose is to provide a torch which is essentially an underwater cutting torch that can be converted quickly for dry land operations as where the metal to be out extends out of the water. 1

Another object is to provide a construction and arrangement of moving parts which will be supported and protected against distorting strains and against jamming.

Anotherobject is to provide a torch which is capable of being constructed long or short without change of essential design in event a particular torch is to be adapted for special work. Furthermore, the present invention provides an underwater cutting torch which is simple in construction and easy to manufacture and service.

These bein among the objects of the invention, other and further objects will' appear from the drawings, the description relating thereto and the appended claims.

- Referring to the drawings:

Fig. 1 is a perspective of the invention showing the preferred form of the torch as connected ready for use.

Fig. 2 is an enlarged perspective of the torch itself shown in Fig. 1 with the head partially cut away to show the preferred head construction.

Fig. 3 is an enlarged medial section taken longitudinally through the head, tip and hood.

' Fig. 4 is an enlarged section taken upon line 4-4 in Fig. 2.

Fig. 5 is a section taken through one of the needle valve compartments showing the improved form thereof.

Fig. 6 is a cross-section through the handle of the torch as taken upon line 6-6 of Fig. 2.

Fig. 7 is an enlarged rear view of the torch body showing position of valves.

Referring now to the drawings in further detail, the underwater cutting torch is indicated generally by the numeral l0 and in Fig. 1 is shown connected to an arrangement of supply tanks in the preferred manner.

Gas supply parts relate to more than one of the four supply lines, beginning with the source of supply and continuing through to the tip.

The hydrogen or acetylene supply for the preheat flame is supplied from a bank of cylinders l2 which have their shutoff valves l3a connected to manifold blocks Ma. The manifold blocks in turn are connected together by pigtails I5a to form a gang. The two cylinders l2, shown in Fig. 1 are representative of a gang of cylinders numbering as many as twelve connected together in the manner described and disposed in any suitable arrangement for the convenience of the connection of the pigtails [5a to the manifolds. The number of cylinders used is selected in relationship to the convenience and the requirements of any particular work project.

The block Ma upon the end cylinder lZa of the bank receives in supported relationship, a pressure reducing regulator lGa which in some instances may be a single stage regulator but preferably is of the two-stage type such as shown in Patent No. 2,362,352, which supplies the fuel to the torch I0 at an adjustable predetermined pressure through the hose Ila.

Oxygen is supplied for the operation of the torch from a bank of oxygen cylinders I! which are connected together in a manner similar to fuel cylinders I2, namely by shutoff valves [3b and pigtails l5b. In the present invention the bank of oxygen cylinders is divided into two supply lines. The end cylinder l'lc of the tank I 1 supports a pressure regulator 16c which supplies oxygen to the torch [0 through a hose Ho for the preheat flame, and a second regulator I6!) is supported on the second cylinder I 1b of the bank I! for supplying a stream of cutting oxygen to the torch through the hose Ill).

The two cylinders llb and He are equalized by a pigtail I50 wherein the manifold Mb has a special side outlet on it to receive one end of the pigtail I50. In this way it is possible to support the two regulators IBD and I60 upon two of the cylinders of a common supply bank I! for use as a dual supply.

With a conventional underwater torch, the oxygen is generally supplied by a single hose to the torch and the stream is then divided in the torch for cutting and preheat operations. As will be readily seen, this arrangement has arisen from conventional practice of converting a dry land torch for underwater operation.

In this regard the present invention is an improvement over the torch conventionally used for underwater cutting. Dry land torches which are subect to atmospheric pressure, work under substantially constant conditions whereas with underwater cutting the back pressure upon the torch is a variable varying with the depth. With the converted conventional torch the out is very often lost upon the cold metal because the preheat flame is bled or robbed of oxygen by the opening of the cutting port. The greater the preheat provided by the torch, the faster the torch will cut, up to the limit that the oxygen supplied is capable of oxidizing the metal. Robbing the preheat flame changes the preheat characteristics enough to create erratic conditions which, if the diver is a little unsteady, slows up the divers potential cutting speed.

The significance of robbing the preheat flame when the cutting oxygen is turned on is greater with increases in thicknesses of metals to be out. With thicker metals the cutting oxygen requirements taxes the capacity of a single supply hose leaving little to maintain an adequate preheat when the cutting stream is turned on. Although the possibility of varying the pressure upon the oxygen supply line can be used to allevia e this dilficulty to some extent, the back pressure at greater depths limits the use of this expediency for that purpose.

A larger hose could be employed but this would be still and unwieldy and be an added burden upon a diver whose physical and mental activity is constantly depressed by the pressure of water upon his body.

The shielding gas which hereinafter will be referred to as air for convenience. sake without being limited thereto, is supplied from a storage tank 2| through the regulator Hid which is connected to the torch by a hose lid. The supply of air available in bank 2| may be. replenished from time to time through the supply pipe 22 connected to a suitable compressor (not shown).

Toacn CONSTRUCTION The torch comprises three main parts, the body 24, the handle 25 including the tubes 26, and a head 21.

Torch body The body 24 is so designed as to be capable of being forged for quantity production with a sep aration of dies being provided along a longitudinally disposed plane indicated by the section line 99 in Fig. 7, it being understood that the body can also be cast.

The four hoses H are secured to the body 24 along parallel lines and although it is possible to provide separate valve assemblies between the hose and the body, it is preferred to form the body so that the valves themselves are mounted in the body for greater strength and ruggedness. For this purpose, as better seen in Fig. 7, the body 24 is provided with four longitudinally disposed ribs 3! into which are longitudinally drilled radially spaced holes 32, one for each rib and a fifth hole 33 in the center of the body.

As shown in Fig. the holes 32a, 32c and 32d are threaded as at 34 to receive nipples 35 Fig. 2 therein to which the hose lines H are connected. The center hole 33 receives an inlet nipple 351), the nipples 35 being threaded loosely into place and soldered in position by silver solder against possible loosening. A surplus of solder is flowed by heat into the corners around the nipple to provide rounded corners and finished appearance which prevents the collection of dirt. The exposed ends of the nipples are machined to provide conical seats 38 which receive spherical headed coupling members 3! in leak-proof engagement. One of the parts is preferably made of bronze and the other of a harder metal such as stainless steel, to eliminate corrosion and provide good contact.

In order to eliminate the danger of connecting the fuel gas line i id to the wrong nipple, the coupling 3'21; and nipple 35a are provided With left hand threads and the remaining couplings and nipples are provided with right hand threads. In view of the fact that the hose lines are connected to the body 24 above surface, there is little likelihood that a mistake would be made when connecting the remaining hose lines to the body, out in event the use of any particular gas other than those described as preferred herein may create a dangerous condition if a mistake should occur, the nipples can be of different sizes as well as of right or left hand turn threads. For instance,

two connections could be left hand threads of dif-' ,does not carry the full pressure of the gas.

ferent sizes and the other two could be righthand threads. of difierent sizes, thus eliminating any possibility of a mistake arising provided the hose line connections at the regulators are provided with the same arrangement.

Referring again to Fig. 5 passageways 38 are drilled diagonally inwardly towards the center of the. body a short distance and radially disposed passageways 4| are drilled to meet them to provide a valve inlet port 42. The radial passage 4! is then reamed and threaded to provide a conical valve seat 43, a downstream valve chamber 44 and two threaded walls 45 and 46 which are separated by a shoulder 41, as spaced radially from each other in a compact manner.

A needle valve 5| seats upon the valve seat 43 as threaded at 52 for adjustment to engage in the threading 45. A shank portion 53 of the valve carries a gland packing 54which rests against the shoulder 41 as held by a gland nut 55. At its outer end, the shank 53 has swaged thereto a circular plate 56 which has three threaded openings 51 therein to receive screws 58 that secure a knurled head 6! thereon. The head 6| has a bell flange 62 suitable for manipulation which covers the gland nut 55 and extends downwardly far enough to barely clear the body rib 3| when the valve is closed, thus preventing articles and obstructions catching under the head 6|.

In this arrangement, the gland packing is disposed upon the downstream side of the valve and Fur-'- thermore, this uniformity of valve structure reduces inventory and provides a rugged serviceable construction which is seasy to manufacture and simple to assemble.

In front of the heads 6| the ribs 3i are provided with faired ridges 63 which prevent weeds catching under the valve heads when the valves are opened as when the torch is lowered through the water. In assembling these valves, the gland nut and shank are tightened into place before the head is secured to the circular plate, the gland nut and packing having been assembled upon the shank before the circular plate was attached thereto.

With this relationship it is to be noted that the body 24 is fluted as at 64 so that the knurled portions of the valve heads extend laterally beyond and overhang the rib contours so that a diver may grip the valve heads and manipulate them quite easily even with heavy diving gloves upon his hands.

Forward of the valve chambers 44a, 44d and 440 passageways 65 are drilled into them from the front of the body 24 according to the pattern show in dotted lines 65a, 65d and 650 as shown in Fig.

The larger hole 321?, as sectionally shown in Fig. 2 is machined to provide a valve chamber 66 and a valve seat 61 at the bottom thereof with a threaded wall 68 which receives therein a valve assembly ll of the diaphragm type comprising a valve cage 12 threaded into the Valve chamber and carrying a holder 73 which supports the valve disc 14 for contact with the valve seat 61. The holder '53 has threaded thereto, a valve stem 15 supported for reciprocation in the valve cage through an opening 16 and a compression spring T! is disposed in the valve cage to force the disc I4 into contact with the seat 61 thereby urging the valve to normally closed position.

The valve cage is provided with a threaded cavity 18 in the outer end thereof to receive a diaphragm 8| supported in a groove 82 upon the valve stem 15. The diaphragm 8| is held in place by a diaphragm cap 83 with the stem 15 extending there-beyond and terminating in a spherical head 84. The valve lever 85 is provided with a key-hole slot 86 which engages the spherical head 84 to operate the valve ll.

The valve chamber 66 is connected to a central opening 33 by a cross-drilled passage 81 which is closed by solder where it passes through the outer wall of the body, and the valve port 88 is connected to the front of the body 24 by a passageway 65b similar to the passages 65a, 65c and 6501.

The lever 85 is pivotally secured to the body by a pin 9! see Fig. 2, mounted in an ear 92 which may be soldered to the body for the sake of economy if the body is forged, or it will be cast integrally with the body if the body is cast. The contour of the ear is such that when the lever is in place no foreign particles can pass beyond it under the lever. The lever i U shaped sectionally with the sides 83 resting against opposite sides of the ear, the sides 83 fashioned with extra length where they engage the ear to extend beyond the pivotal point and provide the key-hole slot 86 already described.

Forwardly of the pivotal engagement the body 24 is provided with two parallel flanges which are machined to provide walls 94 bordering the lever 85 with close clearance to prevent any particles lodging under the lever that would obstruct operation thereof. The walls 94 do not extend any higher than necessary to close the space between the lever and the body 24, both of which are streamlined and tapered to prevent weeds or obstructions catching thereon. The walls 94 also serve to support the lever against lateral strains which might distort it, thereby providing a weedless construction which is very rugged.

Handle Upon the forward end of the body 24 a cylindrical boss I! is provided to receive an exteriorly fluted tubular member I82 which serves as a handle. Within the boss IIJI the passages 65a, 65b, 65c and 65d terminate in four cylindrical openings N13 or counterbores spaced close together in the form of a diamond, openings 1% and 3311 being spaced farther apart than openings I030, and I 03a. The openings receive the tubes 26 all of which are soldered in place upon the body preferably with sufiicient surplus of solder for them to be secured together by the solder as well as secured to the body.

After the tubes 26 are soldered in place upon the body 24 the handle I02 is slipped over the tubes and fastened to the boss IOI by screws, I04. Thereafter, a cap I65 having a corresponding boss Hlla is slipped over the tubes with individual openings (not shown) for receiving each tube snugly. The cap and handle are fastened together by screws I06 leaving a length of the tubes extending forwardly therethrough to receive the head 21. All of the tubes 26 are preferably straight and of the same length so that the length may be easily varied for special reasons if a longer torch is required.

Along one side of the handle H12 an opening I0! is cut therein beneath the lever 85 for the length thereof to clear the lever and a fiat metal piece I88 i bent to follow the contour of the lever and opening as soldered to the handle )2 to prevent articles entering under the lever and obstructing its operations, also providing a lateral support which supports the front end of the lever against strain, v

As more particularly shown in Fig. 2 the lever at the forward end is cut out as at III] to receive the latched member I I l which is pivotally mounted at the forward end of the lever 85 by a transverse pivot pin I [2. The latch has a tooth projection H3 extending towards the handle which is spring urged by a spring H4 to engage in latching relationship with a transverse pin H5 supported by the wall I08. The latch is released by pressure in the same direction that the lever is moved when the valve H is opened. The lever 85 thereby serves as a manual control for the cutting oxygen valve H as locked in its open position by the latch Ill. The spring I I4 operating the latch is lighter in action than the spring 11 of the valve ll so that the latch can be held down at the same time that the lever is held and will permit the lever when so handled to operate as though no latch were present.

The relationship of the parts described thus far is such that when the body and handle are held in the right hand, the lever will be under the control of the thumb so that the torch handle may be held tightly between the fingers and palm without touching the lever, yet, the thumb may operate the lever and unlatch it very quickly and easily. Moreover, as will be seen in Fig. 4 the arrangement of the tubes in the diamond relationship permits the lever to operate closer to the handle since the shortest dimension of the diamond arrangement of the tubes provides a greater clearance for the lever at the opening 101 in the handle.

Thus from the drawing and the description it will be seen that the valves, arrangement of tubes and hose have a predetermined relationship with respect to the location of the lever. This arrangement is different from the conversions made of dry land torches and for a better understanding of the significance of this, it may be well to point out that most dry land cutting torches are operated by the operator below the level of the operators head to prevent slag falling upon the operator. The cutting control lever for dry land torches is upon the back of the handle instead of at the left side, since it is natural to hold a torch under dry land operating conditions with the thumb up. On the other hand, in under water cutting, the diver generally works with the kerf above his head so that a minimum of bubbles obstructs his view. In this position, with the torch slightly to the right, the head of the torch held by the left hand, the most natural way to hold the torch and bear outwardly upon it by the right hand, is to have the thumb to the side and the fingers towards the work, the palm facing away from the diver.

The construction and arrangements of parts shown in the present invention locate the preheat fiame controls where they are most readily accessible to the left hand. The valve Gla, is inwardly and close to the right arm for the control of the fuel supply and the preheat oxygen valve Bic is below the lever where it can be reached by the left hand to control the supply of preheat oxygen. In this way the controls used most often by the diver are arranged for his greatest convenience.

Head

Further novelty resides in the arrangements just discussed in combination with the arrangement of the passages so arranged as to meet with manufacturing expediency wherein the cutting passageway in the tip extends axially through the tip and the preheat gases are grouped around the cutting passageway.

Referring to Fig. 2 the head 21 is substantially L-shaped in its longitudinal section with the bottom portion I 2| provided with four enlarged openings I22 receiving the ends of the tubes 26', the head and tubes being secured together perma nently with silver solder. Upon the back of the head an enlarged portion I23 is provided to serve as an anvil so that the diver can use the torch as a hammer upon occasions when such is required. The arrangement of the tubes in the diamond section in addition to providing clearance for the lever 85, have the longest dimension of the diamond arranged in line with the anvil I23 so that the greatest strength is provided for the torch for hammering.

The front end of the torch has a conical cavity I24 therein, the axis of which is disposed at an angle preferably of 60 to the line of the tubes 26. At its outer end the conical cavity I24 terminates in a cylindrical wall I25 disposed in a boss i26 which is threaded upon the outer portion thereof as at I27 to receive a tip nut I28.

The cutting tip is indicated at I3I as provided with a triple conical seat I32 separated by two longitudinally spaced grooves I33 opposite corresponding grooves I34 cut in the wall of the conical cavity I24. The grooves I33 and I34 in each case provide sealed compartments separated by the seats I32 when the tip I3I is pressed into place. The compartment formed of the grooves I33aI34a is connected with the tube 26a by a drilled passageway I35a in the head 2'! and the compartment I33c-I34c is connected to the tube 250 by a drilled passageway I350 in the body.

It will be remembered that th suffix a indicates the fuel line and the suifix indicates the preheat oxygen supply. The mixture of these two gases takes place in the tip wherein the longil tudinal passageway I36 is drilled from the front of the tip rearwardly into the groove I33a and a cross-drilled passageway I3? is drilled into the passage from the groove I330 at an oblique angle, the passages I36 and I3! representing any one of a plurality of the same that may be required for preheat purposes.

The cutting orifice is a conventional or stepdrilled passageway I38?) drilled at the axial center of the tip and terminating at the base of the tip in communication with a passageway I4Ib connectingthe tube 261) and the bottom of the conical cavity I32.

Forwardly of the last conical seat I32 the diameter ofthe tip at I42 is less than the diameter of the wall I25, thus providing a cylindrical compartment beyond the third seat which compartment is in communication with the tube 266! through a passageway I35d drilled in the body 27.

Beyond the cylindrical portion I42 the tip is shouldered as at I43. The tip nut I28 is a cylindrical member internally threaded at both ends upon opposite sides of an internal radial flange I44 which engages the shoulder I43 to hold the tip in place when the tip nut I28 is threaded into place upon the body 21. The flang I44 is apertured as at I45 to permit the transmission of air forwardly therethrough from the passageway I35d. Beyond the flange I44, where the tip nut I28 is threaded, an externally threaded hood I46 is received in supported relationship as secured against relative rotation by a knurled jam nut I41.

Improved preheat and cutting is provided by the construction and arrangement of the hood and tip, and although the structural characteristics to be described may be adapted for tapering tips, illustration is made in which the tip has a cylirfilrical outer contour I43 beyond the shoulder 3.

For purposes of illustrating an operative device, the diameter of th cylindrical portion I48 may be considered to be /2". The internal contour of the hood is substantially that of a venturi whose largest diameter at the rear is {-t from which it tapers to it at the throat over a length of about 1%", and beyond the throat follows a surface of revolution which has a sectional curve of 2 radius. Beyond the throat the hood is castellated as shown at I5I to a depth of 1%" with six milled slots "wide.

With this construction the air supply passes through the throat of the venturi and creates a relative lowness of pressure in front of the tip that shields the flame from any back pressure at any depth, the air pressure itself being varied as to depth to maintain this condition.

Furthermore the present invention by providing separate supplies of oxygen for preheating and cutting, not only eliminates the robbing of the preheat but provides an independency of the two oxygen supplies which in combination with the Venturi design just described frees the cutting supply of oxygen from any restraints concerning preheat so that regardless of depth, once the preheat is adjusted the torch may be used to cut any thickness of metal merely by changing the cutting supply of oxygen, preheat being unaffected thereby, and vice versa.

In addition to this, further improvements can be made in the cutting tip to satisfy the different problem of deep underwater cutting, and, although the improved torch is essentially an underwater torch, it can readily and easily be adapted for above water cutting whenever upon occasion such is required. This feature-affordsthe advantage that only one type of torch need be provided in the standard locker equipment for ships, shipyards and bridge building work.

In some respects it is diflicult to account fully for the improved results which are obtained by the method and apparatus of this invention, and it should be understood that any attempt to analyze the theory which is believed to be responsible for these results is to be construed not as defining a mode of operation, but merely as a possible explanation of certain physical phenomena which have been observed.

Consequently, although a single embodiment of the invention has been shown and described herein, within the intents and purposes of the objects set forth in the beginning of the description, and various dimensions have been indicated for the purpose of illustration, it will be apparent to those skilled in the art that these dimensions may be varied if compensatory changes are made in other parts, and, it will be further apparent that further and various uses, modifications and changes may be made without departing from the spirit and substance of the invention, the scope of which is commensurate with the appended claims.

What is claimed is:

1. In an underwater cutting torch the combination of a torch head having a threaded portion and a gas supply cavity therein whose wall defines a surface of revolution coaxial with the threaded portion, a tip having a base mating with said cavity in gas transmitting sealed relation and having an outer end extending beyond the head with a portion thereof provided partment, a castellated hood threaded into the with an external wall defining a surface of revolution extending to the end of the tip, and hood means received on the said threaded portion to enclose the outer end of the tip, and having a portion of its internal wall defining a surface of revolution terminating outwardly in a castellated diverging wall rounded convexly beyond the end of the tip, said external wall on the tip and the internal wall on the hood means defining an annular passageway whose walls converge gradually to a Venturi throat located at the end of the tip ahead of said diverging wall.

2. In an underwater cutting torch the combination of a torch head having a threaded portion and a gas supply cavity whose Wall defines a surface of revolution coaxial with the threaded portion, a tip having a base mating with said cavity in gas transmitting sealed relation and having an outer end extending beyond the head with a terminal external wall portion thereof defining a surface of revolution, hood means for enclosing the outer end of the tip including a tip nut received on said threaded portion and holding the tip in place, and a hood element received upon the tip nut and having its internal wall defining a surface of revolution terminating outwardly in a diverging castellated wall convexly rounded at a point beyond the end of the tip, said external wall on the tip and the internal wall on the hood element defining an annular passageway whose walls converge gradually to a Venturi throat located at the end of the tip ahead of said diverging wall.

3. An underwater cutting torch comprising a tip provided with a conical base having longitudinally spaced annular grooves divided by sealing surfaces, outlets in said grooves leading to the point of the tip, a head receiving the tip in sealed relation at said sealing surfaces, gas supply passages through the head including one beyond each end of the conical surface, said head having a cylindrical enlargement defining an annular compartment with the tip, a tip nut threaded on the head and having a flange holding the tip in place, said flange having a plurality of openings therein adapted to communicate with said annular comtip nut, and a jam nut threaded upon the hood to hold the hood against rotation, said hood having converging walls therethrough encompassing said tip and in communication with the annular compartment through the openings in said flange.

4. For use with an underwater cutting torch, a hood comprising a body exteriorly threaded at the back end of the body to be supported with respect to a tip, a central passageway through the body tapering in a direction away from the rear end to a Venturi throat, and terminating in a castellated wall defining a divergent mouth having convexing rounded edges.

5. For use with an underwater cutting torch, a hood comprising a body threaded to be adjustably mounted at the back end of the body and with respect to a tip, a central passageway through the body tapering forwardly to a Venturi throat and terminating in a diverging mouth bounded by a castellated wall providing circumferentialiy spaced radially disposed recesses in the front end of the body with the total area of the recesses less than the overall area of the Venturi throat.

6. For use with an underwater cutting torch having a tip, a hood comprising a body threaded to be adjustably mounted at the back end of the body and with respect to the tip, a central passageway through the body tapering forwardly to a Venturi throat and terminating in a diverging mouth bounded by a convexly rounded edge having circumferentially spaced recesses therein with the area of the space between the tip and the body in the ratio of approximately 1 to 5 with the overall area of the Venturi throat.

7. For use with an underwater cutting torch having a tip, a hood comprising a body threaded to be adjustably mounted at the back end of the body with respect to the tip, a central passage through the body tapering forwardly to a Venturi throat and terminating in a diverging mouth bounded by a castellated wall having a rounded edge, the castellations in th wall comprising spaced radially disposed recesses,'the space between the tip and the wall of the Venturi throat at the end of the tip being less than one-half the total area of said recesses.

FREDERICK N. WINDSOR. 

